On assignment for National Geographic, wildlife and conservation photographer Christian Ziegler was tasked with an unusually specific and difficult commission: to photograph bonobos in the wild. It hadn’t been done for more than 20 years but he succeeded, in the Democratic Republic of the Congo (DRC).

"I spent more than four months in the field to take portraits of this amazing species. It was really tricky – bonobos are an endangered species, they are rare and super shy. I was deep in the jungle for many weeks and at first I didn’t even see any bonobos, but with the help of primatologists I was able to locate and follow a group until they accepted me.

"I specialise in photographing tropical forests and their species, so this project fits within that broader perspective, but this was a very specific and personal assignment. I was the first person to have photographed a bonobo in the wild for more than 20 years."

I needed to follow the group for hours on end – often 14 hours every day, covering more than 20km.

A single lens set-up

"I was shooting on a Canon EF 300mm f/2.8L IS II USM lens, which is compact and super sharp. I love this lens – it was the only one I used during this assignment, usually with a Canon Extender EF 1.4x II. I followed the group for hours on end – often 14 hours every day, covering more than 20km – so I worked with a very simple camera set-up that I could carry for long periods. This lens was an ideal companion for this mission!

"In the run-up to this shot, I was waiting behind a giant fallen tree for the bonobo group to appear. As I was hiding there, this four-year-old youngster climbed onto the tree and just looked at me for a few seconds… then his mum came and took him away. I only had seconds to get the shot but it was an overwhelming moment – the young bonobo looked so gentle and kind."

Tracking bonobos

"Bonobos only exist in DRC – a country that has experienced violent war for many years. These wars have limited development of infrastructure, driven corruption and, ultimately, have limited the country’s capacity to conserve this amazing species.

"I arrived in DRC a few years after the official end the war. My aim was to tell the story of bonobos – they are closer to humans than chimpanzees, and yet we know so little about them. I wanted to tell the world that bonobos exist and also that they are in real trouble.

"This image makes me smile every time – it’s one of my favourites. In that moment, I felt like we (me and the young bonobo) understood each other. It was a very honest encounter."